The present invention relates to a structure of a three hands type clock in which a second hand shaft which carries a second hand and is disposed separately relative to hour and minute hand shafts which respectively carry, hour and minute hands.
A three hand type wristwatch in which a second hand shaft which carries a second hand and is disposed separately relative to hour and minute hand shafts which respectively carry hour and minute hands, has heretofore been constructed such that the hour and minute hands are disposed separately from the second hand on the same dial, and power is transmitted to the hour and minute hands as well as to the second hand through a train wheel structure inside a single watch movement.
There has also been known a similar three hands type wall clock in which hour and minute hands and a second hand are disposed in two different locations on the same dial, and separate clocks movements are provided for driving the hour and minute hands and the second hand, respectively.
However, in the former structure in which the hour and minute hands and the second hand are disposed in two different locations and are operated with the train wheel structure inside the single watch movement, the number of elements of the train wheel is necessarily increased, thereby resulting in the problems of increased cost and deteriorated reliability due to the greater number of parts. Further, because the mutual positional relationship between the two indication portions is determined by the train wheel, there is another problem of limiting the degree of freedom in clock design.
In the latter structure in which the hour and minute hands and the second hand are associated with separate movements for driving the corresponding hands, the two indication portions are free from the limitation in the mutual positional relationship, so the degree of freedom in clock design is improved. However, there are problems that cost is increased due to the need of using two clock movements, and a discrepancy may occur in time indications because of difference in basic frequencies of quartz crystals between the two movements.